Those interested in a night sky unencumbered by the glare from artificial light love to tell this story: When the Northridge earthquake knocked out power in Los Angeles in 1994, calls came into emergency centers and even the Griffith Observatory from people who had poured into the streets in the predawn hours. They had looked into the dark sky to see what some anxiously described as a “giant silvery cloud” over the shaken city.
Not to worry, they were assured. It was merely the Milky Way, the vast galaxy that humans once knew so well — until the glare from electric light effectively erased most traces of it from urban and near-urban skies.
It’s easy to forget, 130 years after outdoor electric lighting first cast its glow through the night, that the sky is actually full of stars. But some are working to show that darker skies can be achieved with new products and technologies.
Because much of Arizona is mountain-studded desert with only two major urban sprawls, Phoenix and Tucson, the state has long been a center for astronomical research.
In the late 1950s, during a time of national resolve to take the lead in space exploration, a cluster of federally funded observatories was built atop the 2,130m Kitt Peak, 90km southwest of Tucson in the Sonoran desert.
But scientists at the Kitt Peak facility, operated by the National Optical Astronomy Observatory, quickly decided that they had to be more than stargazers on a mountaintop. Almost from the beginning, they reached out to form alliances with politicians, lighting engineers and businesspeople, who might be persuaded that dark skies could also be a civic asset.
Tucson passed laws restricting light pollution and emerged as the center of the so-called dark-sky movement. It’s the home of the International Dark-Sky Association, which works to raise awareness about light pollution and to promote the design and marketing of outdoor lighting that has a minimal impact on the night skies.
“Its original roots were in protection of dark skies for astronomical purposes, but very early on the Dark-Sky Association began working with industry and designers,” said Christian Monrad, who owns an electrical engineering company in Tucson and is president of the association’s board.
Initially, it was not an easy sell. Sure, the stargazers wanted dark skies on their mountaintop, but myriad others balked — including car dealers, city lighting engineers, police officials and owners of hamburger stands, malls and security companies. After all, for many of their purposes, brighter was naturally presumed to be better.
Perceptions changed once industry began developing new fixtures with shields that “put the light on the ground where you want it,” Monrad said.
Businesses and politicians also paid attention when it was demonstrated that blazing lights created unnecessary glare that often makes it harder to see clearly.
The Dark-Sky group estimates that badly designed outdoor lighting wastes US$10 billion in energy a year. It issues a seal of approval for a wide range of lighting products, for uses including home landscaping, sports and recreation fields and shopping mall parking lots.
Regulations that limit unnecessary ambient light or require outdoor fixtures to be shielded are in effect in at least 30 states, Monrad said.
The benefits to science are obvious. But the movement has gained momentum because of growing concerns about energy conservation.